How to Destroy a Date
by xXxanimexXxnightcorexXxlover
Summary: Rin always had a soft spot for his little sister Gou and that hasn't changed too much, but when she flirts and makes a date Captain Mikoshiba right in front of him, he can't take it. Now he'll do whatever he can to make sure their first date will be they're last… (Lots of SeiGou because those two are just precious and overprotective Rin)
1. Chapter 1

**Disclaimer**

**Hey everyone, so here's a new SeiGou fanfic because I just love those two together. Also overprotective Rin comes out xD Please feel free to tell me what you think, I'd love to hear your comments and suggestions :3**

**Also, I don't own Free Iwatobi Swim Club (because if I did there'd be more SeiGou xD)**

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The sound of splashing water and excited voices emanated from the Samezuka Academy pool. An energetic, red haired captain blew his whistle to get his teams attention. Most of the exhausted team members huddled around their captain…all but one, who still streaked through the water.

"Yosh, good job everyone," Captain Mikoshiba said bringing his hands together, "Why don't we take break."

He was the captain of the team so of course he believed in hard work, but he also knew there had to be some limits…and one second year with pointy teeth had yet to learn that lesson. Captain Mikoshiba raised his eyebrow as he heard the sound of someone pulling out of the water. He turned to see Rin pull up and reset himself for another lap.

He sighed, "Oi, Matsuoka, didn't you hear what I said?" the Captain asked already knowing his response.

"I don't need any break," Rin said snapping on his goggles, "A break won't benefit me, so there's no point in having one."

The captain smiled and walked over to Rin. With great force he gave him an energetic slap to his back.

"Ah alright then Matsuoka," Captain Mikoshiba said with a laugh, "Just don't strain yourself too much," he said as he slapped Rin's back a few more times.

Rin flinched, "OW, okay I get it!" Rin exclaimed annoyed as the captain just laughed it off. Just then, one of the second year boys called the captain.

"Captain, there is a visitor here," he said.

The captain raised an eyebrow, "Hm, okay, let them in."

The boy nodded and opened the door. The captain's eyes widened and then lit up at the sight of a certain red haired first year girl walk in slowly. Her red hair tied up into a high ponytail, and her Iwatobi swim club jacket draped around her shoulders, slightly falling off to reveal her uniform.

"Excuse the intrusion," Gou said meekly as she scanned the room. Her face lit when her eyes found the spot where her brother and the Captain.

"Tch," Rin said when he caught sight of Gou. He couldn't put up with another distraction.

"Onii-chan! Captain Mikoshiba!" Gou greeted happily as she ran towards them.

Captain Mikoshiba could feel his heart skip. _Gou-kun greeted me…_he thought happily.

"Ah Gou-kun, fancy seeing you here," The Captain said energetically.

"Captain Mikoshiba…the name Gou is boyish enough, must you and –kun after it?" Gou asked with a pout that made the Captain blush slightly which he nonchalantly hid with his usual laugh.

"Gou," Rin called with annoyance in his voice, "I thought I told you to limit your visits. I'm really busy so go home."

_Ouch…_Captain Mikoshiba thought. He couldn't help but see Gou's slight hurt expression. He didn't like it. To him Gou looked best with that smile of hers.

"Ah, don't be like that Matsuoka," The captain said giving Rin another _hard_ slap to his back.

"Ow! Stop that!" Rin exclaimed, "Anyway Gou, just go home for now, I can't hang around with you today."

Gou pouted and then thought for a second. Then to Rin's surprise a smile formed on her face.

"Who said I came to see you Onii-chan?" Gou replied with a hint of teenage attitude.

"Huh?!" Both the Captain and Rin said simultaneously. Gou smiled at his reaction while Rin regained his composer.

"Well, then who'd you come to see?" Rin asked annoyed and maybe even slightly jealous.

Gou smiled, "I came to see Captain Mikoshiba," she said happily as she pulled on the Captain's arm and clung to his side.

This time the captain couldn't hide his blush. A deep crimson color stretch across his face and blended in with the sides of his hair. _W-what's going on with my heart rate?_ The Captain thought as Gou clung harder to his arm. The happiness inside him couldn't be explained.

Rin on the other hand looked like an atomic bomb ready to blow. Rin had noticed the Captain's growing affection towards his sister and he had tried his best to control his disapproval, but this was crossing the line. Did his absence when he was in Australia make Gou forget that he was in fact her _older_ brother? And that she was flirting and clinging to his captain right in _front_ of himHe. This was too much for him to just keep inside. Maybe he could deal with her socializing with the Captain when she visited, or letting him call her by her first (despite his disapproval before), but clinging to a males arm who clearly had interest in her right in front of him was way too much for him to handle, and Gou knew it.

"Gou! What the hell do you think you're doing?!" Rin exclaimed, flaring his pointy teeth, "Get off the Captain now!" Rin ordered. Gou mercilessly ignored him and gripped the Captains arm even harder.

"It's okay," the Captain said as he smiled and rubbed the back of his neck with his free hand, "I don't mind."

_Like hell I know __**you**__ don't mind…_Rin thought angrily.

Gou ignored her brother's murderous aura and turned towards the Captain who could help but smile widely at his situation. Gou was actually clinging to him and he was ecstatic, even if it was just to anger her brother.

"Captain Mikoshiba are you free tomorrow?" Gou asked with a small blush and an adorable grin.

_Wait…did Gou-kun just ask me out…_The Captain thought shocked. Was he dreaming…because if he was he didn't ever want to be woken up.

"Um, Captain Mikoshiba?" Gou asked waving her hand in front of his unblinking eyes.

"YES!" Captain Mikoshiba exclaimed loudly as he took Gou's hands in his own. He could hear Rin growl in the background, but at that moment he didn't care. "Yes, yes, a million time yes, I'm free anytime," the captain babbled.

_Oh my god he sound like such a dork…but it's cute, _ Gou thought with a laugh.

"Really? You can really meet up with me tomorrow?" Gou said excited.

"Of cour-" The Captain began to say until Rin cut him off.

"He can't," Rin said bluntly causing the two to turn towards him to see him wearing a killer expression, "Captain, if you have forgotten we have a little something called practice tomorrow."

"Oh, that's right," Captain Mikoshiba said as he pondered.

"Oh, I'm sorry I didn't know," Gou said with clear disappointment on her face. The Captain flinched, he couldn't bare to see Gou upset. From the corner of his eye he could see Rin smirk in victory.

"Maybe some other ti-" Gou began to say until the Captain frantically cut her off.

"No, wait!" the Captain said causing Gou to look up with hopeful eyes, in turn making the captain blush slightly. The Captain cleared his throat and blew his whistle signaling his team.

"Alright everyone, because of your hard work and due to an urgent arrangement, practice tomorrow is cancelled, Captains orders," Captain Mikoshiba said in and energetic voice. From the corner of his eye he could see Gou smile which caused him to smile too. Before the team could celebrate a day off Rin spoke up.

"What!" Rin exclaimed angry, "Urgent arrangement my ass, you can't just cancel practice because of a date!"

Once Rin said this numerous whistles and congrats came from the other team members which the Captain took with a victorious smile while Gou held her hands in front of her crimson blush. Rin grit his shark like teeth at the total opposite reactions he was going for.

The Captain turned towards Rin with a somewhat victorious smirk and walked up to him and delivered a few more slaps to his back.

"Ah don't worry about anything Matsuoka, if you want to practice tomorrow, you can do it to your heart's content," the Captain said as he continued to slap his back.

"Ow! Damn, stop!" Rin exclaimed.

"O-onii-chan," Gou called slightly worried.

"Don't worry Gou-kun, Matsuoka's like a steel bar," The Captain reassured her, "A few slaps to the back won't kill him," he said as he delivered another hit.

"Don't just assume that!" Rin exclaimed as he flinched, "And anyway, you can't date Gou so tell everyone practice is still on."

"Wait…" Gou called, "Why can't he date me?"

Rin's eyes widened at her question. He looked around anxiously as Gou and the Captain looked at him, waiting for his answer. Rin clenched his fist and pulled off his goggles.

"Tch, do whatever you want," Rin said annoyed.

Gou laughed, "_Whatever_ I want," she asked mischievously. She was really toying with him today, but hey, it was his fault for being so distant all the time.

"H-huh, no…uhh just go home already Gou," Rin said flustered and defeated. Gou and the Captain laughed at his childishness.

"I think you've teased him enough," Captain Mikoshiba said to Gou.

"Yea I guess you're right," Gou said with a laugh, "So I'll see you tomorrow then." She said as she started to walk towards the door.

"Yep!" The Captain said as he smiled happily knowing that she wasn't just teasing her brother about that.

"Bye Onii-chan, Captain Mikoshiba!" Gou said waving as she was about to leave. The Captain waved back with a smile while Rin grunted, still upset from before.

"Ah don't be like that Nii-chan," the Captain said teasing Rin.

"Don't call me that!" Rin said flaring his teeth angrily until a thought dawned upon him. His frown quickly turned into a smirk.

"Captain, do you know when or where you are meeting Gou?" Rin asked with a dark smirk. Captain Mikoshiba raised his eyes and looked up as he thought.

"Uh, no, but I'll just text her," The Captain said with a laugh.

"Hmmm," Rin said with a smirk, "Do you even have her contact number?"

At this the Captain stopped laughing and immediately reached to find his phone and scrolled through his contacts. Rin's smirk widened.

"Ah…no," Captain Mikoshiba said lowering his head in defeat, but then immediately raised it and turned towards Rin.

"Matsuoka, can you give me Gou-kun's number?" the Captain asked in a pleading voice.

Rin smirked in a way that put every other villain's smirk to shame, "Why of course Captain, give me your phone."

Captain Mikoshiba handed Rin his phone while Rin pondered for a _specific_ number in mind. Once he remember it he quickly typed it in and tossed the phone back to the Captain.

"Thanks Matsuoka, I got to go figure out what to wear so later!" The Captain said energetically as he ran out. Once he was gone Rin walked up to his first year roommate.

"Nitori, I'm going to need to switch phones with you for a while," Rin said holding out his phone.

Nitori looked at him confused, but he couldn't say no to his sempai so he reach for his phone, "Sure thing Sempai…but what do you need it for?" Nitori asked.

Rin smirked, displaying his sharp teeth, "I'm just going to help my baby sister with her first date." And with that Rin took the phone and headed to the door, leaving Nitori alone.

Nitori looked down at Rin's phone in his hand and sighed, "Better watch out Captain, it's attack of the six foot Onii-chan…"

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**Oh no what is big brother Rin going to do? I don't think that smirk of his was a good sign...Well, we'll find out in the next chapter :D**


	2. Chapter 2

**Hey guys I'm back! Sorry I haven't been posting frequently...things were happening here and there, plus there was some nasty writers block, but here's chapter 2! Enjoy :3**

**I do not own Free! Iwatobi Swim Club**

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The red haired older brother paced back and forth in his room as he scrolled through his roommates phone. He thought long and hard about what he was going to do, but whatever happens, he had to make sure his little sister would never want to date that speedo wearing Captain ever again.

He tapped his foot as he pondered at the best way to start his plan. The whole time he wore a smirk that would have knocked any villain onto their butt. While Rin plotted silently, his first year roommate watched in confusion from his top bunk.

"Uh, Sempai…are you sure your sister won't be mad if she finds out what you're doing?" Nitori asked concerned. Rin turned with a raised eyebrow.

"She won't be mad…cause' there's no way she's going to find out," Rin said and then turned to his roommate, "Right Nitori…" Rin said in a dark voice that caused Nitori to flinch.

"R-right Sempai!" Nitori responded immediately. Rin smirked and sat on his bed as he started to write a text.

_Now, how would that idiot captain text Gou? _Rin pondered. If this plan was going to work, he had to make sure every detail was perfect. After giving it some thought he wrote down the text:

_Hey Gou-chan! Its Captain Mikoshiba :D I pestered your brother to get your number so I could ask you where we were going to meet up tomorrow…I'm really looking forward to it! (°u°)_

Rin shivered as he finished the text. The thought of Mikoshiba texting his sister like this was just plain gross in his mind. After reading over it he clicked the send button and slouched back in satisfaction. Just then Nitori peered down from his bunk.

"Um, Sempai, I'm just curious…what happens when the Captain tries to text your sister and no one replies?" Nitori asked perplexed.

Rin sighed, "You're a slow one aren't you Nitori…" Rin said slouched forward, "I gave the Captain the number for your phone so I could pretend to be Gou since he already has my number."

Rin sat with eyes closed silently as he waited for Nitori's response, but he didn't say anything. Perplexed Rin opened his eyes only to draw back violently as Nitori stared at him with sparkling eyes only inches from his face.

"The hell Nitori! What is it?!" Rin exclaimed, irritated that he had been caught off guard.

"Sempai, you know my number by heart," Nitori said with an overly happy voice as he then continued to rant on and on about how he has the best sempai and what nonsense.

Just as a vein popped in Rin's forehead, "SHUT UP ALREADY!"

The hot summer like sun beat down on the hard working Iwatobi Swim Club members. They were all hard a work trying to improve their times, giving each other support. Now that they had pretty much reconciled with Rin, things were not as tense, however Rin was still working hard as ever, and that meant that they could slack off either.

As the members continued to train, their team manager sat happily by the side, clipboard in hand, as she thought of some new regimens. Her dark red hair laid in a sloppy ponytail; many loose hung around her face, hiding the slight blush that grazed her cheeks as she reminisced on what had happened earlier. Her silence had not gone unnoticed as the Iwatobi boys exchanged perplexed glances with one another.

"Gou-chan, why do you look so spaced out?" Nagisa asked as he came out of the pool, spreading drops of water around as he dried his hair.

Gou flinched as drops of water landed on her face, "Hey!"

From the distance she could here Makoto and Rei laugh quietly causing her to burrow her face in her clipboard.

"You do look a bit dazed," Makoto said curiously, "Did something happen?"

"Didn't you go see Rin earlier?" Haru asked, still in the water.

"Ah, y-yea I did," Gou stuttered, feeling her face heat up slightly.

"Did something good happen?" Rei asked as he wiped the water off the inside of his goggles.

"N-nothing in particular," Gou said hiding her face behind her sleeves. Normally they would have just left it at this, but unfortunately for her, the shota was on his game today.

"Hmmmm~" Nagisa said suspiciously, "Something must of happened cause' your blushing Gou-chan!" This caught everyone's attention as they exchanged curious looks.

"W-what! No I'm not!" Gou exclaimed only causing herself to blush more.

"Wait!" Nagisa exclaimed excitedly, "Could it be that Captain Mikoshiba finally made his move?!"

At this Gou's entire face turned as red as her hair. She did nothing but bury her face in her palms and try to pretend she had not just thoroughly embarrassed herself. The Iwatobi boys exchanged amused glances as Gou tried not to look up.

"Actually…I asked him…" Gou said, catching everyone by surprise.

"I didn't think you liked the Captain that way," Makoto said slightly surprised.

"Well…" Gou began to say guiltily as she looked at her hands, "At first I only did it to annoy my brother…but after thinking about it, I'm getting kind of nervous, I mean I've never been on a date before," Gou admitted embarrassed. The boys smiled at one another as they looked at their flustered manager.

"Don't worry Gou-chan," Nagisa said happily, "We'll help you get ready!"

"That's right," Rei said, "If anyone knows the beauty of fashion and presentation it is me," he said with a prideful look.

Makoto chuckled, "I'm sure you'll be fine, the captain seems like a decent guy," he said reassuringly.

"I'm surprised Rin's cool with this," Haru said, finally getting out of the water.

"Ah, I wouldn't say he's _completely _cool with it," Gou said with an awkward laugh, just as she felt a vibration in her jacket. Surprised, she pulled out her blinking phone and flipped open the cover.

"Unknown number?" Gou read out loud. She opened the text, and the Iwatobi boys watched as Gou furrowed her eyebrows in confusion.

"What's the matter Gou-chan?" Nagisa asked leaning over her shoulder as he read the text. "It just looks like a text from the captain."

"I know…" Gou said warily, "But, it doesn't sound like him…"

"Huh?" Rei and Makoto said simultaneously.

"Well, Captain Mikoshiba calls me 'Gou-kun,' but here in the text he said 'Gou-chan' he's never called me that," Gou said perplexed, "No matter how much I told him not to call me Gou-kun he wouldn't stop so I don't see why he'd suddenly change it…"

"Hm," Rei pondered, "Makoto-sempai, didn't you exchange numbers with the fellow captain at our first joint practice as formality?"

"Uh, yea I think so," Makoto replied.

"Gou-san, Makoto-sempai, may I have your phones please?" Rei asked in detective mode. Gou and Makoto nodded as they handed Rei their phones. Rei shifted through the contacts intensely and then finally stopped as he displayed a victorious smirk.

"Just as I hypothesized, these numbers do not match," Rei said pushing his glasses into place.

"What! So this wasn't captain Mikoshiba?" Gou asked.

"No, most likely some imposter trying to give you two a hard time," Rei informed.

"Yea! Way to go detective Rei-chan!" Nagisa cheered.

"But who'd want to pull a prank on you?" Haru asked.

Gou pondered for a while, "I don't know…" Gou said slowly, and then it hit her. Rin.

"Brother!" Gou suddenly exclaimed frustrated that caught everyone off guard.

"Rin-chan?" Nagisa asked.

"Makes sense," Makoto and Haru replied.

"I know he's mad I interrupted his practice but this is low!" Gou said with a pout.

_I don't think that's what the reason was… _The boys thought simultaneously.

Gou crossed her arms annoyed as she thought for a while, and then an idea dawned on her. A smirk similar to that of her brother's managed to find its way slyly on her lip as she turned to the swim club members. She immediately flipped open her phone and wrote a rapid text. When she was finished she looked up with satisfaction.

"Makoto-sempai, can I use your phone please?" Gou asked pleadingly.

"Uh, sure," he said handing her his phone, "But what are you planning?"

At this Gou laughed slightly, innocence still edged in her voice, "I think it's time my brother got a taste of his own medicine…."

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**Oh no, I guess evil runs in the Matsuoka family. What does Gou have in mind to scare her brother now?! Stay tuned ;3**


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